Peel and dice the potatoes into 1-inch bite-sized pieces. Place in a large pot, cover with cold water, and bring to a boil. Cook for 10 to 12 minutes until just fork-tender. Drain and set aside.

In a large pot or Dutch oven, combine the chicken stock, diced sweet onion, salt, pepper, and 1 cup of cold water. Bring to a gentle simmer over medium heat and cook for about 20 minutes, stirring occasionally.

In a separate saucepan, melt the butter over medium heat. Gradually sprinkle in the flour while whisking constantly. Whisk for 2 full minutes until the mixture turns pale golden and smells slightly nutty.

Slowly pour the roux into the simmering broth in a thin, steady stream while whisking continuously. The soup will begin to thicken within a couple of minutes. Keep whisking to smooth out any lumps.

Pour in the heavy whipping cream and stir gently to combine. Let the soup simmer uncovered for an additional 10 minutes, stirring occasionally to prevent sticking.

Gently fold in the boiled, drained potatoes. Stir to distribute evenly. Taste and adjust salt and pepper as needed.

Ladle into bowls and top each serving with shredded cheddar cheese, crispy bacon crumbles, and diced green onions. Serve immediately while hot.